@modelcontextprotocol/sdk
Version:
Model Context Protocol implementation for TypeScript
132 lines • 5.03 kB
JavaScript
import { Client } from '../../client/index.js';
import { StreamableHTTPClientTransport } from '../../client/streamableHttp.js';
import { CallToolResultSchema, LoggingMessageNotificationSchema, } from '../../types.js';
/**
* Multiple Clients MCP Example
*
* This client demonstrates how to:
* 1. Create multiple MCP clients in parallel
* 2. Each client calls a single tool
* 3. Track notifications from each client independently
*/
// Command line args processing
const args = process.argv.slice(2);
const serverUrl = args[0] || 'http://localhost:3000/mcp';
async function createAndRunClient(config) {
console.log(`[${config.id}] Creating client: ${config.name}`);
const client = new Client({
name: config.name,
version: '1.0.0'
});
const transport = new StreamableHTTPClientTransport(new URL(serverUrl));
// Set up client-specific error handler
client.onerror = (error) => {
console.error(`[${config.id}] Client error:`, error);
};
// Set up client-specific notification handler
client.setNotificationHandler(LoggingMessageNotificationSchema, (notification) => {
console.log(`[${config.id}] Notification: ${notification.params.data}`);
});
try {
// Connect to the server
await client.connect(transport);
console.log(`[${config.id}] Connected to MCP server`);
// Call the specified tool
console.log(`[${config.id}] Calling tool: ${config.toolName}`);
const toolRequest = {
method: 'tools/call',
params: {
name: config.toolName,
arguments: {
...config.toolArguments,
// Add client ID to arguments for identification in notifications
caller: config.id
}
}
};
const result = await client.request(toolRequest, CallToolResultSchema);
console.log(`[${config.id}] Tool call completed`);
// Keep the connection open for a bit to receive notifications
await new Promise(resolve => setTimeout(resolve, 5000));
// Disconnect
await transport.close();
console.log(`[${config.id}] Disconnected from MCP server`);
return { id: config.id, result };
}
catch (error) {
console.error(`[${config.id}] Error:`, error);
throw error;
}
}
async function main() {
console.log('MCP Multiple Clients Example');
console.log('============================');
console.log(`Server URL: ${serverUrl}`);
console.log('');
try {
// Define client configurations
const clientConfigs = [
{
id: 'client1',
name: 'basic-client-1',
toolName: 'start-notification-stream',
toolArguments: {
interval: 3, // 1 second between notifications
count: 5 // Send 5 notifications
}
},
{
id: 'client2',
name: 'basic-client-2',
toolName: 'start-notification-stream',
toolArguments: {
interval: 2, // 2 seconds between notifications
count: 3 // Send 3 notifications
}
},
{
id: 'client3',
name: 'basic-client-3',
toolName: 'start-notification-stream',
toolArguments: {
interval: 1, // 0.5 second between notifications
count: 8 // Send 8 notifications
}
}
];
// Start all clients in parallel
console.log(`Starting ${clientConfigs.length} clients in parallel...`);
console.log('');
const clientPromises = clientConfigs.map(config => createAndRunClient(config));
const results = await Promise.all(clientPromises);
// Display results from all clients
console.log('\n=== Final Results ===');
results.forEach(({ id, result }) => {
console.log(`\n[${id}] Tool result:`);
if (Array.isArray(result.content)) {
result.content.forEach((item) => {
if (item.type === 'text' && item.text) {
console.log(` ${item.text}`);
}
else {
console.log(` ${item.type} content:`, item);
}
});
}
else {
console.log(` Unexpected result format:`, result);
}
});
console.log('\n=== All clients completed successfully ===');
}
catch (error) {
console.error('Error running multiple clients:', error);
process.exit(1);
}
}
// Start the example
main().catch((error) => {
console.error('Error running MCP multiple clients example:', error);
process.exit(1);
});
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